Senior Software Engineer - AI Fintech foundation (UK)

Machine Learning Engineer

Hopper's Fintech Foundation team sits at the centre of the company's mission: reshaping how more than 100 million monthly active users experience travel. It owns the pricing engine that balances customer demand against financial risk across dozens of partners — including Capital One, Air Canada, and Spirit Airlines. As an ML engineer on this team, you will directly shape how Hopper prices ancillary products in real time and at scale.

About the Role

As a Software Engineer on the Fintech Foundation team, you will design, build, and evolve the machine learning systems that power Hopper's pricing engine. Your work will have direct impact on revenue, financial risk management, and the customer experience across the full partner portfolio.

You will work closely with the Data Science, Engineering, and Product teams to deliver pricing solutions that are reliable, scalable, and oriented toward commercial outcomes.

What would your day-to-day look like

• Design and implement automated, reusable training pipelines to ensure consistent, scalable model delivery across the partner portfolio

• Build ETL pipelines with thoughtful feature engineering to guarantee clean, reliable inputs for pricing models

• Develop and deploy real-time ML pricing solutions to production, owning the full path from model to live environment

• Monitor production systems for latency, drift, and training-serving skew, optimising continuously to maintain model integrity

• Run champion-challenger tests on pricing and product construction levers to surface improvements and respond to shifting market conditions

• Partner with data scientists, engineers, and product stakeholders to translate business needs into well-scoped technical solutions

An ideal candidate has

• 5+ years of experience in a similar role, ideally within production ML systems or large-scale pricing platforms

• Proficiency in Python, Scala, and SQL, applied to production ML systems rather than exploratory work

• Experience in data modelling, software architecture, and distributed data processing frameworks at scale

• Deep understanding of ML algorithms and when to apply them in the context of pricing, demand forecasting, or similar commercial domains

• Strong analytical instincts and attention to detail, with a track record of catching issues before they reach production

• A product mindset that keeps the customer outcome in view, even when the work is deeply technical

• Clear, collaborative communication skills that hold up across data science, engineering, and business stakeholder audiences

Perks and Benefits of working with us

• Well-funded and proven startup with large ambitions, competitive salary, upsides of pre-IPO equity packages.

• Hopper covers 100% of the premiums for the employee for a group insurance plan through Vitality Health.

• Automatic contributions when you start with Hopper through Smart Pension.

• Please ask us about our very generous parental leave, much above industry standards!

• Access to co-working space on demand through FlexDesk AND Work-from-home stipend.

• Carrot Cash travel stipend.

• Unlimited PTO.

• Entrepreneurial culture where pushing limits and taking risks is everyday business.

• Open communication with management and company leadership.

• Small, dynamic teams = massive impact

More about Hopper

At Hopper, we are on a mission to become the leading travel platform globally – powering Hopper's mobile app, website and our B2B business, HTS (Hopper Technology Solutions). By leveraging massive amounts of data and advanced machine learning algorithms, Hopper combines its world-class travel agency offering with proprietary fintech products to bring transparency, flexibility and savings to travelers globally. We have developed several unique fintech solutions that address everything from pricing volatility to trip disruptions – helping people travel better and save more on their trips.

The Hopper platform serves hundreds of millions of travelers globally and continues to capture market share around the world. The Hopper app has been downloaded over 120 million times and has become largely popular among younger travelers – with 70% of its users being Gen Z and millennials.

While everyone knows us as the Gen Z and Millennial travel app, Hopper has evolved to become much more than that. In recent years, we've grown into a travel fintech provider, commerce platform, and global travel agency that powers some of the world's largest brands.

Through HTS, our B2B division, the company supercharges its partners' direct channels by integrating our fintech products on their sites or powering end-to-end travel portals. Today, our partners include leading travel brands like Capital One, Nubank, Air Canada, and many more.

Here are just a few stats that demonstrate the company's recent growth:

• Billions of dollars worth of travel and travel fintech are sold through Hopper and HTS' channels every year.

• Our fintech products – including Cancel for Any Reason and Flight Disruption Assistance – have exceptionally strong CSAT because the terms are always clear, and customers receive instant, no-questions-asked resolutions.

• Almost 30% of our app customers purchase at least one fintech product when making a booking; and consumers are 1.6x more likely to repurchase if they add fintech to their booking vs if they booked just travel.

• Given the success of its fintech products, Hopper launched a B2B initiative, HTS (Hopper Technology Solutions), which represents more than 75% of the business.

• Through HTS, any travel provider (airlines, hotels, banks, travel agencies, etc.) can integrate and seamlessly distribute Hopper's fintech or travel inventory on their direct channels. As its first HTS partnership, the company partnered with Capital One to co-develop Capital One Travel, a new travel portal designed specifically for cardholders. Other HTS partners include Air Canada, Uber, CommBank, Nubank, Flair Airlines and many more.

• Hopper has been named the #1 most innovative company in travel by Fast Company Hopper has been downloaded over 120 million times and continues to have millions of new installs each month. Hopper is now the #3 largest online travel agencies in North America and 70% of our app customers are Gen-Z and millennials travelers.

• Hopper has raised over $750 million USD of private capital and is backed by some of the largest institutional investors and banks in the world. HTS is primed to continue its growth as the leading travel ecommerce provider in a $1 trillion online shopping category. The Hopper app and website will also continue to be the preferred travel provider for Gen Z and Millennials.

Come take off with us!